پديد آورندگان :
ﺣﺴﻨﯽ، ﻓﺎﻃﻤﻪ داﻧﺸﮕﺎه رﻓﺴﻨﺠﺎن - ﮔﺮوه ﺧﺎﮐﺸﻨﺎﺳﯽ , ﺧﺎدم اﻟﺮﺳﻮل، ﻋﻄﺎاﻟﻪ داﻧﺸﮕﺎه ﺷﻬﯿﺪ ﭼﻤﺮان اﻫﻮاز - داﻧﺸﮑﺪه ﮐﺸﺎورزي - ﮔﺮوه ﺧﺎﮐﺸﻨﺎﺳﯽ , ﺷﮑﻔﺘﻪ، ﺣﺴﯿﻦ داﻧﺸﮕﺎه ﺟﯿﺮﻓﺖ - داﻧﺸﮑﺪه ﮐﺸﺎورزي - ﮔﺮوه ﺧﺎﮐﺸﻨﺎﺳﯽ
كليدواژه :
خاكهاي شور و سديمي , اصلاح كننده ي خاك , مديريت پايدار , پايداري خاكدانه , رطوبت خاك , زغال زيستي
چكيده فارسي :
ﺷﻮر و ﺳﺪﯾﻤﯽ ﺷﺪن ﺧﺎكﻫﺎ، از ﺟﻤﻠﻪ ﭘﺪﯾﺪهﻫﺎي ﺗﺨﺮﯾﺐ ﺧﺎك ﻣﺤﺴﻮب ﻣﯽﺷﻮد ﮐﻪ ﺿﻤﻦ ﮐﺎﻫﺶ ﮐﯿﻔﯿﺖ ﺧﺎك ﺑﻪﻃﻮر ﻓﺰاﯾﻨﺪهاي ﻣﻮﺟﺐ اﻓﺖ ﻋﻤﻠﮑﺮد ﻣﺤﺼﻮﻻت ﺑﻪوﯾﮋه در ﻣﻨﺎﻃﻖ ﺧﺸﮏ و ﻧﯿﻤﻪﺧﺸﮏ ﻣﯽﮔﺮدد. ﯾﮑﯽ از روشﻫﺎي اﺻﻼح و ﺑﻬﺒﻮد ﮐﯿﻔﯿﺖ ﺧﺎكﻫﺎي ﺷﻮر و ﺳﺪﯾﻤﯽ، ﮐﺎرﺑﺮد اﺻﻼحﮐﻨﻨﺪهﻫﺎي آﻟﯽ ﻫﻤﭽﻮن زﻏﺎلﻫﺎي زﯾﺴﺘﯽ و ﮐﻤﭙﻮﺳﺖ اﺳﺖ. در اﯾﻦ ﭘﮋوﻫﺶ زﻏﺎلزﯾﺴﺘﯽ ﺣﺎﺻﻞ از ﺑﺎﮔﺎس ﻧﯿﺸﮑﺮ، ﮐﻨﻮﮐﺎرﭘﻮس و ﭘﻮﺳﺖ ﺳﺨﺖ ﭘﺴﺘﻪ )در ﺳﻄﻮح 2 ،0 و 4 درﺻﺪ وزﻧﯽ( و ﻫﻤﭽﻨﯿﻦ ﮐﻤﭙﻮﺳﺖ ﺷﺎخ و ﺑﺮگ درﺧﺘﺎن )در ﺳﻄﻮح 2 ،0 و 4 درﺻﺪ وزﻧﯽ( و در ﺳﻄﻮح رﻃﻮﺑﺘﯽ )50 ،25 و 70 درﺻﺪ رﻃﻮﺑﺖ ﻣﺰرﻋﻪ( ﺑﻪﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﮐﺎﻣﻼً ﺗﺼﺎدﻓﯽ و در 3 ﺗﮑﺮار و در ﻣﺠﻤﻮع 108 ﻧﻤﻮﻧﻪ ﺑﻪ ﺧﺎك ﺑﺮداﺷﺖ ﺷﺪه از ﻣﻨﻄﻘﻪي ﮐﺒﻮﺗﺮﺧﺎن در ﮔﻠﺨﺎﻧﻪي ﺗﺤﻘﯿﻘﺎﺗﯽ داﻧﺸﮕﺎه رﻓﺴﻨﺠﺎن اﻋﻤﺎل ﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺗﯿﻤﺎر 4 درﺻﺪ زﻏﺎلزﯾﺴﺘﯽ ﺑﻘﺎﯾﺎي ﮐﻨﻮﮐﺎرﭘﻮس و در ﺳﻄﺢ رﻃﻮﺑﺘﯽ 25 درﺻﺪ ﻣﻨﺠﺮ ﺑﻪ ﺑﯿﺸﺘﺮﯾﻦ ﮐﺎﻫﺶ ﭼﮕﺎﻟﯽ ﻇﺎﻫﺮي و ﻣﻘﺎوﻣﺖ ﻓﺮوروي ﺧﺎك ﮔﺮدﯾﺪ. در اﺛﺮ اﻓﺰدون 4 درﺻﺪ زﻏﺎلزﯾﺴﺘﯽ ﮐﻨﻮﮐﺎرﭘﻮس در ﺳﻄﺢ رﻃﻮﺑﺘﯽ 50 درﺻﺪ ﻇﺮﻓﯿﺖ ﻣﺰرﻋﻪ ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ ﻗﻄﺮ ﺧﺎﮐﺪاﻧﻪﻫﺎ ﺑﻪﻋﻨﻮان ﺷﺎﺧﺺ ﭘﺎﯾﺪاري ﺧﺎﮐﺪاﻧﻪﻫﺎ و رﻃﻮﺑﺖ ﺣﺪرواﻧﯽ ﺑﻪ-دﺳﺖ آﻣﺪ. ﻫﻤﭽﻨﯿﻦ اﻓﺰودن ﺗﯿﻤﺎر 4 درﺻﺪي ﺑﻘﺎﯾﺎي ﮐﻨﻮﮐﺎرﭘﻮس در ﺳﻄﺢ رﻃﻮﺑﺘﯽ 70 درﺻﺪ ﻇﺮﻓﯿﺖ ﻣﺰرﻋﻪ ﺑﻪ ﺧﺎك ﺳﺒﺐ اﻓﺰاﯾﺶ رﻃﻮﺑﺖ ﺣﺪ ﺧﻤﯿﺮي ﺷﺪ. اﯾﻦ ﭘﮋوﻫﺶ ﻧﺸﺎن دادﮐﻪ ﮐﺎرﺑﺮد زﻏﺎلﻫﺎي زﯾﺴﺘﯽ و ﮐﻤﭙﻮﺳﺖ ﺑﻪﻋﻨﻮان اﺻﻼحﮐﻨﻨﺪهﻫﺎﯾﯽ ﻣﻨﺎﺳﺐ ﺟﻬﺖ ﺑﻬﺒﻮد وﯾﮋﮔﯽﻫﺎي ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ ﺧﺎكﻫﺎي ﺷﻮر و ﺳﺪﯾﻤﯽ ﻣﺤﺴﻮب ﻣﯽﺷﻮﻧﺪ. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ اﯾﻦ ﭘﮋوﻫﺶ زﻏﺎل زﯾﺴﺘﯽ ﺑﻘﺎﯾﺎي ﮐﻨﻮﮐﺎرﭘﻮس، ﺑﯿﺸﺘﺮﯾﻦ ﺗﺄﺛﯿﺮ را ﺑﺮ روي وﯾﮋﮔﯽ-ﻫﺎي ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ ﺧﺎكﻫﺎي ﺷﻮروﺳﺪﯾﻤﯽ ﻣﻨﻄﻘﻪي ﻣﻄﺎﻟﻌﺎﺗﯽ ﻧﺸﺎن داد. ﺑﺪﯾﻦ ﺗﺮﺗﯿﺐ ﻣﯽﺗﻮان از اﯾﻦ اﺻﻼحﮐﻨﻨﺪهي آﻟﯽ ﺑﻪﻋﻨﻮان ﯾﮏ ﺗﯿﻤﺎر اﺛﺮﺑﺨﺶ در راﺳﺘﺎي ﺗﺤﻘﻖ اﻫﺪاف ﻣﺪﯾﺮﯾﺖ ﺑﻘﺎﯾﺎي آﻟﯽ ﯾﻌﻨﯽ ﺑﻬﺒﻮد وﯾﮋﮔﯽ-ﻫﺎي ﻓﯿﺰﯾﮑﯽ و ﺳﺎﺧﺘﻤﺎﻧﯽ ﺧﺎك از ﻃﺮﯾﻖ اﻓﺰودن ﻣﻮاد آﻟﯽ ﻣﻨﺎﺳﺐ ﺑﻪ ﺧﺎك، ﺑﻬﺮهﻣﻨﺪ ﺷﺪ.
چكيده لاتين :
Introduction Soil is the upper layer of earth in which plants grow and is consequently very important for organisms and human nutrition. The protection of the soil against degrading processes, such as soil salinization and alkalization, is one of the main challenges in sustainable land management. Soil salinization and alkalization are two major environmental concerns leading to soil degradation especially in arid and semi-arid regions across the world. The balance of organic carbon in the soil is important for soil sustainability. Intensive cultivation enhance soil organic carbon (SOC) depletion. In order to alleviate the detrimental effects of SOC depletion, carbon-rich organic amendments such as biochar or compost are often applied to the soil. Therefore application of organic amendments to soil is an effective strategy to improve soil properties and to mitigate the negative impacts of inappropriate management strategies. Biochar is a carbon-rich compound produced by the pyrolysis of biomass in oxygen-limited conditions. Its use as an organic amendment to soil with specific inherent characteristics has been recognized. In this regard recent studies have shown that application of biochar to soil as an organic amendment can improve soil physical properties and help to keep the carbon balance in the soil. Moreover, compost as an organic amendment is capable to improve soil properties and increase the soil productivity.
Methods and Materials The soil sampling was carried out near Kabutar Khan in Rafsanjan, Iran (56°22′N, 30°18′E), on a saline-sodic soil with Silty Clay soil texture (42% silt, 50% clay and 8% sand). The biochar was obtained from three different feedstocks consist of Conocarpus erectus, bagasse of Sugarcane and hard shell of Pistacia Vera. The obtained feedstocks were pyrolyzed at 400°C for 2 h with increasing rate of 7 °C/min in a sealed reactor to prevent O2 input (Muffle Furnace, SEF-101 Model). Afterwards the produced biochar was cooled slowly to the room temperature, then the EC, pH, specific surface area and CHNS of biochars were measured using the standard methods. The required amounts of soils and biochars were weighed by a total 5000 g dry weight of sample and mixed in the dry state. The soil samples were received three doses of biochar (0, 2, 4 % biochar, w/w). The mixtures of soil and biochar were packed into pots and controlled a bulk density of about 1.5 g cm-3 by artificial compaction. Treatments were replicated three times. The soil without any biochar was used as the control. The mixtures were wetted at three soil moisture contents (25, 50 and 75% field capacity) during incubation time (120 days). The treatments were kept at a temperature-controlled glasshouse. After 120 days of incubation, the untreated soils and biochar-amended soils were taken for physical and chemical analyses.
Particle size distribution was measured by hydrometer method and soil organic carbon by oxidation method with potassium dichromate. The consistency limits (liquid limit and plastic limit) of soils were determined according to the ASTMD4318 procedure. The field capacity was measured using the pressure plates with the standard rings in the lab. Mechanical strength is a sensitive indicator of the soil physical condition and has been commonly used to evaluate soil water erosion, structural stability, tillage performance, and root penetration. Higher strength found in saline-sodic soil often impedes seedling emergence and root penetration. Remolded soil cores were saturated by capillarity for 24 h, equilibrated on a pressure plate apparatus for 12 h, and dried at 105 °C for 2 h. The dried soil cores were placed horizontally between two parallel plates of a digital unconfined compression apparatus, and the pressure was gradually increased through the plates by a motor at a constant speed of 2 mm min−1 approaching the soil core. The maximum reading was recorded before the core was fractured by the load plate.
Results and discussion Our results revealed that application of organic matter in the form of biochars and compost was effective on soil aggregation. The formation and stability of the soil aggregates play an important role in the crop production and soil degradation prevention. Moreover, the biochar application showed two main effects including direct and indirect effects. Our results confirm the addition of biochar to soil can cause a substantial and significant change in the soil physical characteristics of the strongly acidic Ultisol, namely a significant increase in LL and PI, higher water-holding capacity, and reduction in mechanical strength. These changes are undoubtedly associated with the particular properties of biochar and in particular with its high porosity and low bulk density. The beneficial effect of biochars on soil physical properties is mainly due to the dilution effect of biochar with higher porosity and lower density. When the biomass is heated, volatile matters may release out of the biomass to create micropores on the surface, and meanwhile those trapped inside the biomass are evaporated to expand the microstructure. Thus, the resulting biochar has much higher surface area and porosity. These properties are particularly useful for soil application of biochar especially for enhancing soil water-holding capacity, reducing mechanical strength, and increasing soil aggregation. The dilution effect can be attributed to the increased volume of pores as well as the decreased particle density in soil amended with biochar. The effectiveness of different biochars in improving the soil physical properties can be explained by their porosity and bulk density.
Conclusion Our results depicted that application of biochars and compost as an organic amendments improved mechanical quality of the saline and sodic studied soil. Indeed all organic treatments decreased bulk density and enhanced soil aggregate stability while the biochar of Conocarpus illustrated the greatest effectiveness on soil physical and mechanical properties. Therefore it is a possibility to apply this biochar to the soil in the field scale but regarding the accessibility of biochar of Pistachio skin in the study area therefor we have another alternative to utilize in the soil. This research was conducted in the small scale and in a short time. Therefore, it is suggested that supplementary studies are carry out on farm scale for a longer periods.
